1. Field of the Invention
The present invention generally relates to a portable electronic device, and particularly to a cooling structure for cooling a heat-generation electronic component of a portable electronic device such as a notebook personal computer or a laptop computer.
2. Description of the Related Art
Recently, with the widespread use of notebook personal computers for improving the efficiencies of tasks, there has been a strong demand toward multi-function of the computers. To satisfy such a demand, the packing densities of printed circuit boards built in notebook personal computers have become higher, and consequently electronic components liable to generate large amounts of heat have come to be mounted on the printed circuit boards at high densities. Further, in notebook personal computers, the power consumptions of integrated circuits have been increased due to high clocking thereof, and correspondingly the heat-generation amounts thereof have been increased. From this viewpoint, it has been required to effectively cool such heat-generation electronic components. In particular, for notebook type or laptop type portable information processing devices, heat-generation components are concentratedly built in a main body portion, and accordingly, when the portable information processing device is placed on a desk for example, heat is less escaped from the bottom surface of the main body portion, resulting in the temperature rise of the bottom surface of the main body portion.
In the recent portable information processing devices, the heat-generation amount of a CPU tends to be increased due to a higher operational frequency of the CPU, and to efficiently radiate such heat, it is effective to make use of the forced air-cooling by a cooling fan. For example, a technique has been known, in which a fan heat sink integrated with a plurality of radiating fins and containing a cooling fan is brought into area-contact with a CPU, whereby the CPU is forcibly air-cooled by the cooling fan.
This prior art cooling structure for heat-generation components is configured such that mounting fixtures are disposed on the back surface of a printed circuit board on which the CPU is mounted, and the fan heat sink is fixed to the mounting fixtures by screwing in a state in which the printed circuit board is held between the fan heat sink and the mounting fixtures. In the cooling structure, to ensure a sufficient degree of adhesion between the fan heat sink and the CPU, coil springs are inserted between the mounting fixtures and a plurality of portions, to be screwed, of the fan heat sink, whereby the fan heat sink is pressed toward the printed circuit board by biasing forces of the coil springs.
Since most of heat generated from a CPU is radiated via a heat sink, the heat sink must be enlarged with an increase in heat-generation amount of the CPU, which inevitably leads to enlargement of an electronic device including the CPU. Such enlargement of the heat sink, however, is undesirable because it is most essential to reduce the size and weight of a portable information processing device.
An object of the present invention is to provide a portable electronic device capable of efficiently radiating heat generated from a heat-generation component.
Heat generated from a heat-generation component such as a CPU mounted on an electronic device can be expected to be radiated not only by the forced air-cooling due to air blasting by a fan of a fan heat sink but also by thermal transfer from a main body of the heat sink to another component and spontaneous emission to atmosphere.
In accordance with an aspect of the present invention, there is provided a portable electronic device including: a casing; a metal made main frame contained in the casing; a printed circuit board contained in the casing in such a manner as to be directed substantially in parallel to the main frame; a heat-generation component mounted on the printed circuit board; a cooling device disposed in contact with the heat-generation component for cooling the heat-generation component; and a metal made fixture for fixing the cooling device to the main frame.
With this configuration, since the cooling device is directly connected to the main frame, heat generated from the heat-generation component is transferred to the main frame via the cooling device, and is radiated from the main frame. The main frame having a large heat capacity and a large surface area functions as an optimal radiating member. In this way, according to the present invention, heat generated from the heat-generation component mounted on the portable electronic device can be efficiently radiated.
In accordance with another aspect of the present invention, there is provided a cooling structure for an electronic device having a heat-generation component, including: a metal made main frame; a printed circuit board on which the heat-generation component is mounted, the printed circuit board being mounted substantially in parallel to the main frame; a cooling device disposed in contact with the heat-generation component for cooling the heat-generation component; and a metal made fixture for fixing the cooling device to the main frame.
The above and other objects, features and advantages of the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description and appended claims with reference to the attached drawings showing some preferred embodiments of the invention.